浑善达克沙地南缘农牧交错带弃耕地植被的演替规律

 以浑善达克沙地南缘农牧交错带不同年限弃耕地为对象,研究了不同年限弃耕地植物群落特征。结果表明:弃耕地的植被演替一般经历4个阶段:1年生杂草阶段、丛生小禾草阶段、多年生根茎禾草阶段和多年生丛生禾草阶段;地上生物量的变化与弃耕年限不是单一的直线关系,且随弃耕年限的增加,多年生植物的地上生物量占地上总生物量的百分比逐渐增大。对不同放牧干扰下弃耕地植被群落特征进行了研究,结果表明:在弃耕地植被演替的第1、2阶段不宜利用,但在弃耕地植被演替的第3、4阶段,可以进行适度利用;随着弃耕年限的增加,只要不对地表土壤进行破坏,弃耕地都会发生进展演替,并达到一个偏顶级群落,然后又会在放牧干扰下,发生逆行演替。

Succession disciplinarian of vegetation in abandoned land in agricultural cross bedding on south edge of Otindag sandy land

The characteristics of plant communities on abandoned land in different years were surveyed in agricultural cross bedding in the south edge of Otindag sandy land. The results showed that there were four stages in the whole succession of abandoned land, including annual weeds stage, overgrowth grass stage, perennial root grass stage and perennial overgrowth grass stage; changes of total over ground biomass and the abandoned time was not a linear dependence relation, and with increasing of time, the proportion of perennial grass over ground biomass in the total over ground biomass increased too. By comparing the characteristics of plant communities in different pasture disturbances, another result was gained that abandoned land shouldn't be made use in the first two stages, but appropriate use was allowed in the last two succession stages. Along with increasing years of abandoned plant, as long as surface soil is not destroyed, the land would have a progressive succession and reach the partial climax community, and then would cause regressive succession under pasture disturbance.